The present invention relates to a monitoring and indicating circuit. More particularly, the invention is directed to a voltage monitoring and indicating circuit for monitoring a dc voltage utilized by a circuit or apparatus and for providing an output indication in the event of a loss of the voltage, for example, due to an open circuit condition or a short circuit condition.
There are many applications in which a circuit or apparatus is powered by a dc voltage and in which it is desired to detect a loss of this voltage, for example, due to an open circuit condition or a short circuit condition. The detection of the loss of voltage may be utilized in many different ways, such as initiating an alarm condition, generating a computer interrupt, automatically switching a standby dc voltage source to the circuit or apparatus, activating a so-called "crowbar" circuit to protect the circuit or apparatus from damage or improper operation, or acting as a short term power source itself.